Danish company building massive solar farm in Arizona desert: Why are batteries being installed too?

Deep in the Arizona desert, a Danish company is building a massive solar farm that includes batteries that charge when the sun is shining and supply energy back to the electric grid when it's not.

“Solar farms only produce when the sun shines, and the turbines only produce when the wind blows,” said Ørsted CEO Mads Nipper. “For us to maximise the availability of the green power, 24-7, we have to store some of it too.”

Back in Arizona, Ørsted’s Eleven Mile Solar Center covers 2,000 acres in rural Pinal County. 

It has 857,000 solar panels and more than 2,000 cubes that look like large shipping containers but contain battery modules. Ørsted also has large solar and storage projects in Texas and Alabama, and in Europe.

When the Arizona facility opens this summer, most power from the solar farm will go to Facebook owner Meta's data center in Mesa. The solar power not needed by Meta, in addition to the power stored in the batteries, will go to the local utility's customers. The new batteries can ensure power to roughly 65,000 homes during peak hours of demand.

“What I think is exciting is just how rapidly this market is moving," says Yayoi Sekine, head of energy storage at BloombergNEF. “There's so much pressure for the U.S. and different regions to decarbonize, and storage is one of the major technologies to enable that. There's a lot of momentum."

Why are batteries so crucial to the green transition?

Batteries allow renewables to replace fossil fuels like oil, gas and coal while keeping a steady flow of power when sources like wind and solar are not producing. For example, when people are sleeping and thus using less electricity, the energy produced from wind blowing through the night can be stored in batteries - and used when demand is high during the day.